StarTram

Abstract: The StarTram-C Maglev system launch weight can launch 500,000 tons of cargo/year to orbit ~1000 times present capability, at ~$30/kilogram of payload, ~ 1/300 th of present cost. Magnetically levitated expendable cargo craft accelerate to > 8 km/see in an evacuated ground tunnel using superconducting (SC) Maglev technology now operating in Japan for high speed trains. No propellant is used; energy from the electrical grid costs $0.50 per kg of launch weight. After reaching orbital speed, the levitated cargo craft ascends in a curving evacuated launch tube that is magnetically levitated above Earth’s surface by the repulsion force between SC cables attached to it and an opposing set of SC cables on the surface. The levitation force is 4 tons/meter of tube length at 20 km altitude, and exceeds the tube weight. High strength Kevlar tethers to the ground prevent vertical and lateral motion. Craft enter the atmosphere at 20 km through an open exit that prevents in-leakage of low density air by high speed gas ejectors and an MHD (Magnetic Hydro Dynamic) pump, and coast to apogee, where a small )V burn (~500 m/s) establishes orbit. Deceleration as it enters the atmosphere at 20 km is modest, ~1 g. Peak heating is ~5 KW /cm for times of a few seconds before the craft reaches space. The technology for StarTram-C now exists, and no breakthroughs in materials are required. INTRODUCTION Thirty four years after the first manned landing on the Moon, the cost of space launch remains extremely expensive, currently costing on the order of $10,000 per kilogram of payload to low Earth orbit, and considerably more for higher )V missions. Until launch costs can be greatly reduced, the exploration and exploitation of space will be extremely constrained. Despite the enormous effort during the decades since the Moon landing to develop better and cheaper launch systems, launch costs have come down only marginally. Many different approaches have been proposed and worked on, including expendable rockets, the Space Shuttle, single stage to orbit, scram jets, combined cycle, etc. However, none has succeeded in dramatically reducing launch cost. It appears likely that this pattern will continue, at least for systems that rely on propellant combustion to achieve the )V needed to reach orbit or beyond. Such systems have a small payload fraction, and require that their materials and design parameters be pushed to the limits in order that the payload fraction be greater than zero. This results in a launch system that is complex and operates close to the failure point, and is very

Abstract: StarTram is a new approach for low launch to space using Maglev technology. Spacecraft are magnetically levitated and accelerated without propellants to orbital speeds in an evacuated tunnel at ground level using only electrical energy. The cost of the electric energy for acceleration to 8 kilometers per second is only 60 cents per kilogram of payload. After reaching orbital speed, the StarTram spacecraft coast upwards inside an evacuated levitated launch tube to an altitude, of 10 kilometers or more, where they enter the low‐pressure ambient atmosphere. The launch tube is magnetically levitated by the repulsive force between a set of high current superconducting cables on it and oppositely directed currents in a set of superconducting cables on the ground beneath. High strength Kevlar tethers anchor the launch tube against crosswinds and prevent it from moving laterally or vertically. A Magneto Hydro Dynamic (MHD) pump at the exit of the evacuated launch tube prevents air from entering the tube. Two StarTram systems are described, a high G (30G) system for cargo only launch and a moderate G (2.5 G) system for passenger/cargo spacecraft. StarTram’s projected unit cost is $30 per kilogram of payload launched, including operating and amortization costs. A single StarTram facility could launch more than 100,000 tons of cargo per year and many thousands of passengers. StarTram would use existing superconductors and materials, together with Maglev technology similar to that now operating. The StarTram cargo launch system could be implemented by 2020 AD and the passenger system by 2030 AD.

Abstract: Rocket based Earth to space launch systems are limited to a few hundred tons of payload annually at $~10,000 per kilogram. Over the past 30 years only marginal cost reductions have been achieved. Electromagnetic launch to space can greatly reduce launch cost and increase launch volume. StarTram uses superconducting maglev to accelerate heavy payloads ~20 to 30 tons, to orbital speed, ~8 kms/sec, in evacuated tunnels at ground level. Superconducting 20 ton Maglev passenger vehicles using the 1966 inventions of Powell and Danby now operate in Japan at 360 mph in the open atmosphere limited only by air drag. In evacuated tunnels, orbital speeds are possible. Two StarTram systems are described. The near term Gen-1 system launches 35 ton cargo craft from the surface at a high altitude location, e.g., ~4000 meters. The cargo craft ascends to orbit, where a small delta V rocket burn establishes orbit. Launch energy cost is only ~$0.50 per kilogram of payload. Adding costs of the cargo craft, operating personnel, and the amortized launch facility, total launch cost is only ~$50 per kg, compared to $10,000 per kg using rockets. A single Gen-1 facility can launch over 100,000 tons per year to orbit, 500 times current world capacity. Applications for the Gen-1 system includes greatly expanded Earth monitoring and communications, national defense, beamed power to Earth and robust space exploration. The Gen-1 system is described including Maglev levitation and propulsion, superconducting energy storage, the exit into the atmosphere, and the cargo craft design. Also described are the aerodynamic heating and deceleration forces on the cargo craft as it ascends to orbit. The initial deceleration is ~10 g and nose heating rate is ~20 kW/cm2. Both decrease to zero in a few seconds. Delta V loss through the atmosphere is about 500 meters/sec. Technology for the Gen-1 systems already exists and a Gen-1 facility could operate within 10 years. The U.S., Russia, China and Europe each have the technical capability and suitable high-altitude sites for a Gen-1 system. Potential sites are described. The Gen-2 StarTram system to launch both cargo and passengers is also described. It is a longer term, and requires a magnetically levitated launch tube to reach high altitude.